1. Field of the Invention
This invention relates to a data reproducing apparatus for reading information out of a plurality of tracks of a recording medium.
2. Related Art and Prior Art Statement
Conventional recording media are floppy discs and hard discs which record and reproduce data by using magnetism and optical discs and optical cards which record and reproduce data by using light and they can record large volumes of data. On these recording media, the data are properly divided in response to the lengths of the tracks and are recorded as pit rows along the tracks. For example, the respective tracks are formed adjacently in parallel. Also, in the optical discs, for example, the tracks are Spirally formed and therefore the respective tracks are peripherally formed in parallel. Each track has a data region in which a track number is recorded and, after this track number, data are recorded.
Now, in the case of reproducing the data recorded on the above mentioned recording media, as it is general that the tracks on the recording media are read in one by one and the data are reproduced, a plurality of adjacent tracks will be simultaneously read in and the data will be able to be reproduced.
Usually, in the data reproducing apparatus, in the case of reading data, a seeking operation will be made. In this seeking operation, a reading head is moved toward an objective track, then, while rotating (in the case of a disc-like medium) or reciprocating (in the case of a card-like medium) the medium, focusing or tracking is made, the read signal of "0" or "1" of the information recorded on the recording medium is binary value generated, the binary value generated reproduced signal is demodulated and the track number of the above mentioned track is thereby read in and confirmed. When the seeking operation is completed and this track is the objective track, the data of this track will be read. In case it is not the objective track, seeking will be made anew. In case the objective track number can not be read in as a result of making a provided number of seeks, for example, due to a flaw or dirt on the medium, a seeking error will be made and the data also will not be able to be read. In such case, even if there is no error in the data, the reading will be also impossible.
The case of simultaneously reading in a plurality of tracks is also the same. When a plurality of tracks are simultaneously read and an operation of independently reading in all the tracks is made, in case the track number can not be read in, the data of this track also will not be able to be read in. For example, as mentioned in the publication of Japanese patent application laid open No.141932/1990, there is disclosed an apparatus for reading in data by simultaneously radiating light spots to a plurality of tracks. In this apparatus, it is into one track part that the read signal is instantaneously read and the data of the rest of the tracks are recorded in a memory.
Therefore, when the track number of the track instantaneously read in can not be read, the objective reproducing position will not be able to be guaranteed, a seeking error will be made and it will not be permitted to read in the data.
As described above, in the conventional data reproducing apparatus of a system of reading in one track, there is a defect that, in case the track number of the moving end can not be read out due to a flaw or dirt on the recording medium, the data also will not be able to be read. Also, as in the apparatus mentioned in the above mentioned publication, even if the system of simultaneously reading in a plurality of tracks is adopted, if the track number of the track instantaneously read in can not be read, after all the data will not be able to be read in. This fact leaves a space to be improved.